In this paper, we propose the design of fiber optic refractive index sensor based on a thin core fiber, sandwiched between an input and output single mode fibers. This structure is characterized by a refractive index sensitivity about 187.98 nm/RIU (refractive index unit). In order to enhance the sensitivity, we designed a tapered single mode-thin core-single mode fiber structure where the sensitivity with different waist-diameters (90, 60 and 30 μm) is investigated. As a result, we obtained an ultra-high sensitivity of the tapered sensor about 783.19 nm/RIU in the refractive index range of 1.3346-1.3899, using sucrose and water mixture solution, achieved for a waist diameter equal to 30 μm and a taper length of 675μm.The designed structure presents the merits of high sensitivity which is 4 times higher than that of the thin core fiber modal interferometer which makes it an excellent candidate for biochemical sensing applications.
In this paper, we propose a design of a high numerical aperture multimode hybrid step-index fiber for mid-infrared (mid-
IR) supercontinuum generation (SCG) where two chalcogenide glass compositions As40Se60 and Ge10As23.4Se66.6 for the
core and the cladding are selected, respectively. Aiming to get accurate modeling of the SCG by the fundamental mode,
we solve the multimode generalized nonlinear Schrödinger equations and demonstrate nonlinear coupling and energy
transfer between high order modes. The proposed study points out the impact of nonlinear mode coupling that should be
taken into account in order to successfully predict the mid-infrared supercontinuum generation in highly nonlinear
In this paper, we propose a design of a multimode step index fiber where the first six modes can propagate simultaneously. We investigate the propagation of six strongly coupled groups of modes which are very important for spatial division multiplexing (SDM) optical communications. We solve numerically the six coupled Manakov equations and we find that fundamental solitons propagating in different groups of modes travelling with the same speed due to spectral shifts for each soliton. This phenomenon is known as soliton trapping and is a consequence of the intermodal nonlinear coupling based on cross phase modulation. This fiber is very promising to increase the capacity of SDM systems by more than a tenfold factor compared to single mode systems.